What is Night Effect?

What is Night Effect?

• A. It has no effect on reception
• B. Interference due to ionosphere height changes around sunrise and sunset
• C. Interference caused by precipitation static
• D. It only occurs at high altitude

Answer: (B)

Night Effect is the interference in radio reception that occurs when the ionosphere’s height changes around sunrise and sunset. As the sun moves across the horizon, the ionospheric reflection layer shifts, creating slightly different propagation paths for the same signal. When those paths combine at the receiver, their differing phases can cancel or reinforce each other, causing flutter, fading, or sudden reception changes. This phenomenon is tied to the day–night transition and is about ionospheric propagation conditions, not precipitation static, and it isn’t limited to very high altitudes.

Night Effect is the interference in radio reception that occurs when the ionosphere’s height changes around sunrise and sunset. As the sun moves across the horizon, the ionospheric reflection layer shifts, creating slightly different propagation paths for the same signal. When those paths combine at the receiver, their differing phases can cancel or reinforce each other, causing flutter, fading, or sudden reception changes. This phenomenon is tied to the day–night transition and is about ionospheric propagation conditions, not precipitation static, and it isn’t limited to very high altitudes.